Increased attention is being given the world over to pedestrian-vehicle impacts as more vehicles appear on the roadways, particularly in developing countries. As a consequence, government studies related to the protection of pedestrians in vehicle impact events are also increasing. For example, pedestrian protection has become a goal of the United Nations Economic Commission for Europe. The UNECE advanced a proposal “to develop a global technical regulation concerning the protection of pedestrians and other vulnerable road users in collision with vehicles and final report on the development of the global technical regulation concerning pedestrian safety.” Along with the Global Technical Regulation No. 9 (GTR-9), the European New Car Assessment Programme (Euro NCAP) developed a pedestrian protection star rating system. Vehicle manufacturers must meet child head, adult head, upper leg and lower leg test requirements provided to assess vehicle designs for mitigation of pedestrian injury caused by a vehicle frontal impact.
To reduce pedestrian injuries and to meet current and emerging global safety regulations, automotive companies are implementing Pedestrian Protection Systems. These systems often require additional space under the vehicle's engine hood that either avoid the provision of engine or engine-related components in the Pedestrian Protection Zone or provide for breakaway components that fall out of the zone in an impact event.
Often engine cooling components are, of necessity, located in or near the Pedestrian Protection Zone and are subject to the applicable safety requirements in their design criteria. The coolant reservoir is typically packaged just below the vehicle's engine hood, thus allowing convenient access for coolant fills. This location frequently places the coolant reservoir within the Pedestrian Protection Zone below the engine hood. This situation becomes more complicated as it is desired for the reservoir to be located near the front of the vehicle. Because the gap between the underside of the engine hood and the under-hood components typically reduces toward the front of the vehicle, the coolant reservoir, being typically placed vehicle-forward, is a component that often presents challenges to under-hood component placement and design.
As in so many areas of vehicle technology, there is room for improvement related to the protection of pedestrians in a pedestrian-vehicle impact event.